Communication technologies that network electronic devices are well known. Examples of those technologies include: wired packet data networks; wireless packet data networks; wired telephone networks; and satellite communication networks, among others. These communication networks typically include a network infrastructure that services a plurality of client devices. The Public Switched Telephone Network (PSTN) is probably the best-known communication network and has been in existence for many years. The Internet, another well-known example of a communication network, has also been in existence for a number of years. Communication networks like these enable client devices to communicate with one another on a global basis.
Local Area Networks (wired LANs), e.g., Ethernets, support communications between networked computers and other devices within a serviced area. These wired LANs often link serviced devices to Wide Area Networks (WANs) such as the Internet. Each of these networks is generally considered a “wired” network, even though some of these networks, e.g., the PSTN, may include some transmission paths that are serviced by wireless links.
More recently, wireless networks have come into existence. Examples include cellular telephone networks, wireless LANs (WLANs), and satellite communication networks. Common forms of WLANs include Bluetooth® and IEEE 802.11(a) networks, IEEE 802.11(b) networks, and IEEE 802.11(g) networks some of these networks are referred to jointly as “IEEE 802.11 networks.” In a typical IEEE 802.11 network, a wired backbone couples to a plurality of Wireless Access Points (APs), each of which supports wireless communications with computers and other wireless terminals that include compatible wireless interfaces within a serviced area. The wired backbone couples the APs of the IEEE 802.11 network to other networks, both wired and wireless, and allows serviced wireless terminals to communicate with devices external to the IEEE 802.11 network. Devices that operate consistently with an IEEE 802.11 protocol may also support ad-hoc networking in which wireless terminals communicates directly to one another without the presence of an AP.
Bluetooth® enabled wireless devices allow mobile devices having both low cost and low power consumption. However, these devices cannot use the Bluetooth® protocol to access network resources in a mobile environment that extends beyond the short range of their digital radio systems. Thus, most mobile systems rely on wider range cell networks that consume far more power than Bluetooth® systems. This higher level of power consumption reduces the usefulness of these devices by negatively impacting the battery life of the device.
WLANs can support both voice and data communications via wireless terminals. When supporting voice communications, these wireless terminals often interface with the PSTN through the WLAN. The communications are routed between the PSTN or other WAN and a serviced wireless terminal via a WLAN interfaced to a PBX other like device. Those wireless voice terminals may roam anywhere within the service area of the WLAN and receive voice service. However, should the wireless terminal roam outside of the service area of the WLAN, the call will be dropped. Thus, a need exists for those wireless terminals to roam and be handed off to and serviced outside of the coverage area of the WLAN.